Railroad-wheel trip



1954 c. A. GALLAGHER ETAL 3,151,327

RAILROAD-WHEEL TRIP Filed NOV. 25, 1962 2 Sheets-Sheet l FIG. 3.

INVENTO R5 BY #n ATTORNEY5 Oct. 6, 1964 c. A. GALLAGHER ETAL RAILROAD-WHEEL TRIP 2 Sheets-Sheet 2 Filed NOV. 23, 1962 WWK v INVENTORS CORNELIUS A. GALLAGHER JOSEPH F. McDONALD ATTORNEYS.

United States Patent 3,151,827 RAILROAD-WHEEL TRIP Cornelius A. Gallagher, Hicksville, N.Y., and Joseph F.

McDonald, North Branch, N.J., assignors to Servo Corporation of America, Hicksville, N.Y., a corporation of New York Filed Nov. 23, 1962, Ser. No. 239,695 3 Claim. (Cl. 246-249) Our invention relates to a railroad-wheel trip, that is, to a fixedly mounted device which can respond to the passage of a railroad wheel to develop an electrical output pulse for clearly identifying the instant at which the wheel passes the trip device. This application is a continuationin-part of and embodies modifications of the invention disclosed in our co-pending application, Serial No. 676,- 220, filed July 5, 1957, now abandoned, which embodies modifications of the invention disclosed in our co-pending application Serial No. 627,330, filed December 10, 1956, for Railroad-Wheel Trip, now abandoned.

It is an object to provide an improved device of the character indicated.

It is another object to provide an improved wheel trip which requires no source of electric power supply and yet which can develop a significant and directly utilizable electric output pulse upon the detected passage of a wheel of magnetic flux-conducting material, such as a steel railroad wheel.

It is a general object to meet the above objects with a device of elemental simplicity, and which is relatively inconspicuous and which therefore can be relatively protected against possible damage by such bars, rods, chains or the like as may be dragged by a passing train.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of the invention:

FIGURE 1 is a view in perspective showing a portion of railroad track to which a trip of our invention has been secured;

FIGURE 2 is a vertical sectional view through the rail and trip of FIGURE 1, as viewed in the plane 22 thereof;

FIGURE 3 is a plan view of the trip as viewed substantially in the plane 33 of FIGURE 2; and

FIGURE 4 is a view similar to FIGURE 3 to illustrate a modified form;

FIGURE 5 is an exploded view showing a permanent magnet received in a pocket formed of the same rubbery plastic as the potting;

FIGURE 6 is a sectional view showing the permanent magnet of FIGURE 5 attached to the rail;

FIGURE 7a is an illustration of the output signals from the transducer arrangement of FIGURE 6; and

FIGURE 7]) is a chart showing the output from the transducer embodiment of FIGURE 4.

Briefly stated, our invention contemplates application of a trip element to a section of installed railroad track to monitor the instant at which each passing wheel traverses the trip, as by developing a strong electric output pulse to identify each such instant. The trip comprises a magnetic flux-conducting core element which is permanently magnetized and which is so secured to a part of the rail that a polarized magnetic flux gap is cut or traversed by the flanges of passing railroad wheels. An electric output-signal winding coupled to the core provides means whereby an electric identifying pulse is generated for the passage of each car wheel. The trip assembly may be cast in a rugged potting compound so as to protect the internal 3,151,827 Ce Fatented Oct. 6, 1964 parts and provide an easy means of securing the same to the rail section.

Referring to FIGURES 1 to 3 of the drawings, the invention is shown in application to a generally rectangularly prismatic trip device 10 secured by means 11-12 to the web portion 13 of a section 14 of railroad track. The walls of the trip are preferably contoured to fit snug to the recessed contour of one side of the rail 14, and the top surface 15 is positioned to safely clear any and all wheel flanges, such as the flange 16 of the wheel 17.

In accordance with the invention, the core means 18 is a horseshoe magnet permanently polarized and constituting, in conjunction with the rail head 21, the magneticfiux path whereby a polarized magnetic-flux gap is oriented for traversal by each passing car wheel. The magnet 18 is defined by generally similar opposed upstanding arms or pole pieces 192t), one of which is oriented close to the web 13 and beneath the head 21 of the rail section 14. The vertical spacing of the magnet 18 is preferably such that the outer pole piece or arm 1? safely clears the locus of passing car wheels, as suggested by the lightly dashed outline 22.

With the described orientation, it will be seen that a polarized magnetic flux gap is established generally in the region 23 between pole pieces 19-20. It is substantially through or adjacent this region that all passing wheel flanges 16 must pass, and therefore an electrical winding 24 coupled to a part of the core 18 will develop an electrical signal upon the passage of each such wheel. The winding 24 is shown preferably developed about the outer leg or arm 19 so as to permit mounting the inner leg 24) as close as possible to the web 13 and beneath the head 21.

For ease of mounting, and for weather resistance and security, we prefer that the entire pick-up unit be em bedded in a suitable potting of plastic and cast in the form of a prismatic block 25. This permits complete containment of all internal parts, and also permits contouring the inner surface 26 of the casing so as to fit snugly against tne rail. Also, the described potting permits relatively easy mounting by means of through bolts 11 secured by nuts 12 to the other side of the rail web 13. Preferably, electrical terminals 31 for winding 24 are cast into the potting 25 so that electrical connections may be made by means of conventional lock nuts or the like, as will be understood.

It has been generally indicated that we prefer the upstanding inner arm or leg 20 of the core to be as close as possible underneath the-head 21 of the rail section. Actually, for a symmetrical magnet-core construction, the clearance limitation suggested at 2 2 will prevent contact of the arm 20 with the underside of the rail head 21, and since the rail itself is of magnetic flux-conducting material, it is desirable to employ the head 21 as part of the magnetic circuit so as, in effect, to elevate the location of the flux gap through which the wheel flanges pass. For this purpose, we have illustrated our preference that the arm 20 be slightly extended in reference to the arm 19, and have shown a simple wedge 32 of magnetic fluxconducting material inserted between the top of the leg 20 and the underside of the rail head 21. The entire casting preferably includes the wedge 32, and the upper limit of the casting (at 33) preferably exposes a part of the wedge 32 for direct contact with the underside of the rail head 21; also, care must be taken that the shortest span between opposite poles of the polarized core (including rail head 21) occurs between pole 19 and the nearest edge of the rail head 21, as shown in FIGURE 2. In this manner, it will be understood that the rail head is necessarily part of the magnetic circuit, so that stronger signals may be developed because the wheel flanges traverse a larger section of the gap.

The width of the gap, that is, the spacing of the arm 19 from the adjacent side of rail head 21, is preferably sufiiciently great to take in all wheel flanges, no matter what the lateral or axial play of the wheels in reference to the gage of the rails. For example, the lateral or axial play ordinarily allowed for wheels (with relation to the rails) is of the order of one inch; by comparing the heavy full outline 16 with the phantom outlines 16' of FIGURE 2, representing the extremes of axial play, it may be seen that in all cases flux lines in the gap 23 are cut when the wheel passes the trip. In passage, we find that signals are reliably developed at all times, and that for speeds as low as five miles per hour, the output signal is directly utilizable (without amplification) to actuate various devices, as for example, shutter mechanisms of hot-box detectors as disclosed in greater detail in copending patent application, Serial No. 620,703, filed November 6, 1956, now abandoned.

FIGURE 4 shows a modification embodying basic principles discussed in connection with FIGURES 1-3; corresponding parts have therefore been given the same reference numerals, with primed notation. The FIG- URE 4 arrangement differs in that a larger portion of the rail section 14 is brought into the polarized magnetic path. To this end, the polarized magnetic core 18' is slightly tilted so that the arm thereof may substantially lie against the rail web 13, thus introducing both the rail web 13 and the rail head 21 into the magnetic path, and again establishing the polarized gap between the outer pole 19 and the near or adjacent corner of the rail head 21. Operation is otherwise as described for FIGURES 1-3.

Referring now to FIGURE 5, the magnet comprises two pole ends indicated by the numerals 19" and 20" which ends are the same as in the embodiments previously described. One end of the magnet 19" is received in the opening or pocket 35' of an insulative spacing element 35. The spacing element 35 and potting form a com posite support for the magnet in FIGURE 6. In order to facilitate the molding and to improve the adherence of the magnet to the plastic, a plastic tape 36 may be provided around certain surfaces of the magnet. The remaining elements of the embodiment are the same as described previously in connection with FIGURE 4.

As shown in FIGURE 6, the pole 20 is in substantially direct contact with the head of the rail 21 in the sense that the flux from pole 20" is directly coupled to the rail head 21. The reluctance between the top of the pole 20" and the rail head 21 is substantially less than the reluctance between the pole heads 19" and 20" and between the pole head 19 and rail head 21. Thus, the flux path as established from the rail head 21 to the top of pole 19" is the same as that established in the other embodiments.

The spacing between the pole 20" and the rail 13 and the rail head 21 is such as to substantially reduce or prevent electrostatic coupling between the iron of the rail and the iron of the magnet. The spacing therefore prevents the direct transferral of current surges .in the rail to the magnet due to lightning. However, the spacing is relatively small and is not so great as to affect the establishment of the flux path from the rail head 21 to the pole head 19". A spacing of approximately A" has been found to be practical although variations in such spacing are obviously possible.

The arrangement shown in FIGURE 6 has a certain other advantage in that more uniform pulses are produced. The graph at FIGURE 7a representsthe output from a transducer arrangement as shown in FIGURE 6 while the chart shown in FIGURE 7b represents the output from a transducer arrangement shown in FIGURE 4. As shown in FIGURE 7a, the differential from one signal to another is much less than that shown in FIGURE 7b. As an example, the pair of signals A are more uniform in FIGURE 7a than in FIGURE 7b.

It will be seen that we have described a basically simple device which can be built to withstand extreme abuse, and which requires no external source of power to become operative. In other words, regardless of weather conditions and for an indefinitely long period, the device can be continuously alert to passing trains and can develop a clear electrical pulse output for each passing wheel. The utilization of a part of the rail itself (that is, the adjacent side of the rail head) in the magnetic circuit, makes it possible to enhance the eflectiveness of the outputpulse signal, and also makes it possible to build a device into a substantially protected location beneath the level of the rail and on the inside of the web 13. The extent to which the prismatic body extends laterally inwardly (i.e. towards the opposite rail of the track) is minimal, so that our device presents virtually no obstruction, and maximum protection is afforded against fouling by rods, chains or the like which may be dragged by a passing train.

While we have described the invention in detail for the preferred forms shown, it will be understood that modifications may be made within the scope of the invention as described in the claims which follow.

What is claimed is:

l. A railroad wheel trip, comprising in combination a ferromagnetic rail section including a head and a base portion integrally formed at opposite ends of an up standing web portion,

a railroad wheel having a ferromagnetic flange adapted to ride on one lateral side of said head,

a magnet having oppositely polarized ends,

an electrical winding surrounding a portion of said magnet,

a potting of solid non-magnetic electrically insulating material encasing said magnet and winding,

the potted assembly being of such size as to fit between said rail head and base Within the vertical limits of said web,

electrical leads of said winding extending to an external surface of said potting,

means extending through said web section and the potted assembly fixedly mounting the two parts together,

the magnet being positioned in said potting so that one end of said magnet extends laterally outwardly on said one side of said head,

the other end of said magnet being positioned in substantially direct contact with a part of said rail section above said base so as to transfer its polarization thereto, whereby a polarized gap is defined between said one side of said head and said one end of said magnet, and the gap being located so as to be materially altered by the traversal of said flange on said one side of said head.

2. A railroad wheel trip, comprising in combination a ferromagnetic rail section including a head and a base portion integrally formed at opposite ends of an upstanding web portion,

a railroad wheel having a ferromagnetic flange adapted to ride on one lateral side of said head,

a magnet having oppositely polarized ends,

an electrical winding surrounding a portion of said magnet,

a potting of solid non-magnetic electrically insulating material encasing said magnet and winding,

the potted assembly being of such size as to fit between said rail head and base within the vertical limits of said web,

electrical leads of said winding extending toan external surface of said potting,

means extending through said web section and the potted assembly fixedly mounting the two parts together,

the magnet being positioned in said potting so that one end of said magnet extends laterally outwardly on said one side of said head,

the other end of said magnet being positioned adjacent to a part of said rail section above said base to couple magnetic flux to said section and to transfer its polarization thereto,

said other end of said magnet and said rail section being spaced apart by a relatively small distance to define an insulating spacing therebetween and also to define a polarized gap between said one side of said head and said one end of said magnet,

said polarized gap being located so as to be materially altered by the traversal of said flange of said one side of said head.

3. A railroad wheel trip, comprising in combination a ferromagnetic rail section including a head and a base portion integrally formed at opposite ends of an upstanding web portion,

a railroad wheel having a ferromagnetic flange adapted to ride on one lateral side of said head,

a magnet having oppositely polarized ends,

an electrical winding surrounding a portion of said magnet,

a potting of solid non-magnetic electrically insulating material encasing said magnet and winding,

the potted assembly being of such size as to fit between said rail head and base within the vertical limits of said web,

electrical leads of said winding extending to an external surface of said potting,

means extending through said web section and the potted assembly fixedly mounting the two parts together,

the magnet being positioned in said potting so that one end of said magnet extends laterally outwardly on said one side of said head,

the other end of said magnet being positioned in substantially direct magnetic coupling relationship with a part of said rail section above said base so as to transfer its polarization thereto, whereby a polarized gap is defined between said one side of said head and said one end of said magnet, and the gap being located so as to be materially altered by the traversal of said flange on said one side of said head.

References Cited in the file of this patent UNITED STATES PATENTS 2,231,105 Block et a1 Feb. 11, 1941 FOREIGN PATENTS 112,527 Switzerland Nov. 2, 1925 

1. A RAILROAD WHEEL TRIP, COMPRISING IN COMBINATION A FERROMAGNETIC RAIL SECTION INCLUDING A HEAD AND A BASE PORTION INTEGRALLY FORMED AT OPPOSITE ENDS OF AN UPSTANDING WEB PORTION, A RAILROAD WHEEL HAVING A FERROMAGNETIC FLANGE ADAPTED TO RIDE ON ONE LATERAL SIDE OF SAID HEAD, A MAGNET HAVING OPPOSITELY POLARIZED ENDS, AN ELECTRICAL WINDING SURROUNDING A PORTION OF SAID MAGNET, A POTTING OF SOLID NON-MAGNETIC ELECTRICALLY INSULATING MATERIAL ENCASING SAID MAGNET AND WINDING, THE POTTED ASSEMBLY BEING OF SUCH SIZE AS TO FIT BETWEEN SAID RAIL HEAD AND BASE WITHIN THE VERTICAL LIMITS OF SAID WEB, ELECTRICAL LEADS OF SAID WINDING EXTENDING TO AN EXTERNAL SURFACE OF SAID POTTING, MEANS EXTENDING THROUGH SAID WEB SECTION AND THE POTTED ASSEMBLY FIXEDLY MOUNTING THE TWO PARTS TOGETHER, THE MAGNET BEING POSITIONED IN SAID POTTING SO THAT ONE END OF SAID MAGNET EXTENDS LATERALLY OUTWARDLY ON SAID ONE SIDE OF SAID HEAD, THE OTHER END OF SAID MAGNET BEING POSITIONED IN SUBSTANTIALLY DIRECT CONTACT WITH A PART OF SAID RAIL SECTION ABOVE SAID BASE SO AS TO TRANSFER ITS POLARIZATION THERETO, WHEREBY A POLARIZED GAP IS DEFINED BETWEEN SAID ONE SIDE OF SAID HEAD AND SAID ONE END OF SAID MAGNET, AND THE GAP BEING LOCATED SO AS TO BE MATERIALLY ALTERED BY THE TRAVERSAL OF SAID FLANGE ON SAID ONE SIDE OF SAID HEAD. 